Here are some other terms that may also be included: Confidentiality » the agreement and any information learned will remain confidential. Covenants » things each party must do while negotiations are taking place. Special Terms » any special terms that the parties agree will be in the purchase agreement, such as leaving certain items of furniture or hiring certain employees.
Go with one of the classics, because they're used for a reason. If you sound too stiff and formal, it comes off like a holiday card. If you reiterate your call to action, it can carry a whiff of desperation. Just get out gracefully and quickly once you've said your piece.